This invention relates to the bending assembly of a bending machine for bending rod- and/or bar-shaped workpieces and especially pipes.
Some bending assemblies employ a bending tool and a bending drive unit with a swivel arm and a bending drive motor, with the bending tool featuring at least one workpiece thrust block and at least one thrust pad on the swivel arm, whereby the bending drive motor can rotate the swivel arm with the thrust pad around a bending axis extending in the transverse direction of the workpiece so that, when the swivel arm with the thrust pad is rotated, the workpiece can be bent as it is forced by the thrust pad against the corresponding thrust block.
A bending system of this type, operating by the roll-and-stretch bending principle, has been disclosed in DE-A-40 10 445. In the prior art design an electric bending-drive motor is housed inside a bending bench that protrudes from a machine base and is equipped at its free end with a bending tool. The bending tool includes two bending dies that sit on the two opposite ends of a spindle. The neutral geometric axis of this spindle, i.e., the bending axis, extends in the transverse direction of the workpiece. Also connected to the spindle is a swivel arm which, when the spindle with the bending dies is rotated, can swivel around the bending axis. Clamping jaws that cooperate with the bending dies can be moved on the swivel arm in the transverse direction of the workpiece. For bending the workpiece, the bending dies and the swivel arm are driven by the electric bending-drive motor whose shaft is connected by a gear system to a transmission shaft that extends in the transverse direction of the bending axis. A transfer transmission in the form of a bevel gear drive transmits the rotary movement of the transmission shaft to the spindle that is positioned concentric with the bending axis and supports the bending dies as well as the swivel arm.
This earlier bending drive design and thus the prior art bending system as a whole is relatively bulky, which is especially true with machines providing a substantial transverse bending torque and requiring a correspondingly massive bending-drive motor.
It is the objective of this invention to provide a novel bending assembly that is capable of handling even large transverse bending torques within a compact configuration.